For a bird found near the northern edge of its breeding range, what general timeframe might a first verifiable spring sighting occur?

Answer

Late March through April

If living near the northern edge of the breeding range, the first verifiable sighting of a male establishing territory typically occurs between late March and April as conditions moderate.

For a bird found near the northern edge of its breeding range, what general timeframe might a first verifiable spring sighting occur?
habitatbirdrangenorthmockingbird